Surgical tool having positively positionable tendon-actuated multi-disk wrist joint

ABSTRACT

The present invention is directed to a tool having a wrist mechanism that provides pitch and yaw rotation in such a way that the tool has no singularity in roll, pitch, and yaw. A positively positionable multi-disk wrist mechanism includes a plurality of disks or vertebrae stacked in series. Each vertebra is configured to rotate in pitch or in yaw with respect to each neighboring vertebra. Actuation cables are used to manipulate and control movement of the vertebrae. In specific embodiments, some of the cables are distal cables that extend from a proximal vertebra through one or more intermediate vertebrae to a distal vertebra, while the remaining cables are medial cables that extend from the proximal vertebra to one or more of the intermediate vertebrae. The cables are actuated by a pivoted plate cable actuator mechanism.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/782,833,filed May 19, 2010, which is a division of application Ser. No.10/980,119, filed Nov. 1, 2004, which is a division of application Ser.No. 10/187,248, filed Jun. 28, 2002, now U.S. Pat. No. 6,817,974, whichis based on and claims the benefit of U.S. Provisional PatentApplication No. 60/301,967, filed Jun. 29, 2001, and U.S. Provisionalapplication No. 60/327,702, filed Oct. 5, 2001, the entire disclosuresof which are incorporated herein by reference.

This application is related to the following patents and patentapplications, the full disclosures of which are incorporated herein byreference:

PCT International Application No. PCT/US98/19508, entitled “RoboticApparatus”, filed on Sep. 18, 1998, and published as WO99/50721;

U.S. patent application Ser. No. 09/418,726, entitled “Surgical RoboticTools, Data Architecture, and Use”, filed on Oct. 15, 1999;

U.S. Patent Application No. 60/111,711, entitled “Image Shifting for aTelerobotic System”, filed on Dec. 8, 1998;

U.S. patent application Ser. No. 09/378,173, entitled “Stereo ImagingSystem for Use in Telerobotic System”, filed on Aug. 20, 1999;

U.S. patent application Ser. No. 09/398,507, entitled “Master HavingRedundant Degrees of Freedom”, filed on Sep. 17, 1999;

U.S. application Ser. No. 09/399,457, entitled “Cooperative MinimallyInvasive Telesurgery System”, filed on Sep. 17, 1999;

U.S. patent application Ser. No. 09/373,678, entitled “Camera ReferencedControl in a Minimally Invasive Surgical Apparatus”, filed on Aug. 13,1999;

U.S. patent application Ser. No. 09/398,958, entitled “Surgical Toolsfor Use in Minimally Invasive Telesurgical Applications”, filed on Sep.17, 1999; and

U.S. Pat. No. 5,808,665, entitled “Endoscopic Surgical Instrument andMethod for Use”, issued on Sep. 15, 1998.

BACKGROUND OF THE INVENTION

The present invention relates generally to surgical tools and, moreparticularly, to various wrist mechanisms in surgical tools forperforming robotic surgery.

Advances in minimally invasive surgical technology could dramaticallyincrease the number of surgeries performed in a minimally invasivemanner. Minimally invasive medical techniques are aimed at reducing theamount of extraneous tissue that is damaged during diagnostic orsurgical procedures, thereby reducing patient recovery time, discomfort,and deleterious side effects. The average length of a hospital stay fora standard surgery may also be shortened significantly using minimallyinvasive surgical techniques. Thus, an increased adoption of minimallyinvasive techniques could save millions of hospital days, and millionsof dollars annually in hospital residency costs alone. Patient recoverytimes, patient discomfort, surgical side effects, and time away fromwork may also be reduced with minimally invasive surgery.

The most common form of minimally invasive surgery may be endoscopy.Probably the most common form of endoscopy is laparoscopy, which isminimally invasive inspection and surgery inside the abdominal cavity.In standard laparoscopic surgery, a patient's abdomen is insufflatedwith gas, and cannula sleeves are passed through small (approximately ½inch) incisions to provide entry ports for laparoscopic surgicalinstruments. The laparoscopic surgical instruments generally include alaparoscope (for viewing the surgical field) and working tools. Theworking tools are similar to those used in conventional (open) surgery,except that the working end or end effector of each tool is separatedfrom its handle by an extension tube. As used herein, the term “endeffector” means the actual working part of the surgical instrument andcan include clamps, graspers, scissors, staplers, and needle holders,for example. To perform surgical procedures, the surgeon passes theseworking tools or instruments through the cannula sleeves to an internalsurgical site and manipulates them from outside the abdomen. The surgeonmonitors the procedure by means of a monitor that displays an image ofthe surgical site taken from the laparoscope. Similar endoscopictechniques are employed in, e.g., arthroscopy, retroperitoneoscopy,pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy,hysteroscopy, urethroscopy and the like.

There are many disadvantages relating to current minimally invasivesurgical (MIS) technology. For example, existing MIS instruments denythe surgeon the flexibility of tool placement found in open surgery.Most current laparoscopic tools have rigid shafts, so that it can bedifficult to approach the worksite through the small incision.Additionally, the length and construction of many endoscopic instrumentsreduces the surgeon's ability to feel forces exerted by tissues andorgans on the end effector of the associated tool. The lack of dexterityand sensitivity of endoscopic tools is a major impediment to theexpansion of minimally invasive surgery.

Minimally invasive telesurgical robotic systems are being developed toincrease a surgeon's dexterity when working within an internal surgicalsite, as well as to allow a surgeon to operate on a patient from aremote location. In a telesurgery system, the surgeon is often providedwith an image of the surgical site at a computer workstation. Whileviewing a three-dimensional image of the surgical site on a suitableviewer or display, the surgeon performs the surgical procedures on thepatient by manipulating master input or control devices of theworkstation. The master controls the motion of a servomechanicallyoperated surgical instrument. During the surgical procedure, thetelesurgical system can provide mechanical actuation and control of avariety of surgical instruments or tools having end effectors such as,e.g., tissue graspers, needle drivers, or the like, that perform variousfunctions for the surgeon, e.g., holding or driving a needle, grasping ablood vessel, or dissecting tissue, or the like, in response tomanipulation of the master control devices.

Some surgical tools employ a roll-pitch-yaw mechanism for providingthree degrees of rotational movement to an end effector around threeperpendicular axes. The pitch and yaw rotations are typically providedby a wrist mechanism coupled between a shaft of the tool and an endeffector, and the roll rotation is typically provided by rotation of theshaft. At about 90° pitch, the yaw and roll rotational movementsoverlap, resulting in the loss of one degree of rotational movement,referred to as a singularity.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to alternative embodiments of a toolhaving a wrist mechanism that provides pitch and yaw rotation in such away that the tool has no singularity in roll, pitch, and yaw. In onepreferred embodiment, a wrist mechanism includes a plurality of disks orvertebrae stacked or coupled in series. Typically the most proximalvertebrae or disk of the stack is coupled to a proximal end membersegment, such as the working end of a tool or instrument shaft; and themost distal vertebrae or disk is coupled to a distal end member segment,such as an end-effector or end-effector support member. Each disk isconfigured to rotate in at least one degree of freedom or DOF (e.g., inpitch or in yaw) with respect to each neighboring disk or end member.

In general, in the discussion herein, the term disk or vertebrae mayinclude any proximal or distal end members, unless the context indicatesreference to an intermediate segment disposed between the proximal anddistal end members. Likewise, the terms disk or vertebrae will be usedinterchangeably herein to refer to the segment member or segmentsubassembly, it being understood that the wrist mechanisms havingaspects of the invention may include segment members or segmentsubassemblies of alternative shapes and configurations, which are notnecessarily disk-like in general appearance.

Actuation cables or tendon elements are used to manipulate and controlmovement of the disks, so as to effect movement of the wrist mechanism.The wrist mechanism resembles in some respects tendon-actuated steerablemembers such as are used in gastroscopes and similar medicalinstruments. However, multi-disk wrist mechanisms having aspects of theinvention may include a number of novel aspects. For example, a wristembodiment may be positively positionable, and provides that each diskrotates through a positively determinable angle and orientation. Forthis reason, this embodiment is called a positively positionablemulti-disk wrist (PPMD wrist).

In some of the exemplary embodiments having aspects of the invention,each disk is configured to rotate with respect to a neighboring disk bya nonattached contact. As used herein, a nonattached contact refers to acontact that is not attached or joined by a fastener, a pivot pin, oranother joining member. The disks maintain contact with each other by,for example, the tension of the actuation cables. The disks are free toseparate upon release of the tension of the actuation cables. Anonattached contact may involve rolling and/or sliding between thedisks, and/or between a disk and an adjacent distal or proximal wristportion.

As is described below with respect to particular embodiments, shapedcontact surfaces may be included such that nonattached rolling contactmay permit pivoting of the adjacent disks, while balancing the amount ofcable motion on opposite sides of the disks. In addition, thenonattached contact aspect of the these exemplary embodiments promotesconvenient, simplified manufacturing and assembly processes and reducedpart count, which is particularly useful in embodiments having a smalloverall wrist diameter.

It is to be understood that alternative embodiments having aspects ofthe invention may have one or more adjacent disks pivotally attached toone another and/or to a distal or proximal wrist portion in the same orsubstantially similar configurations by employing one or more fastenerdevices such as pins, rivets, bushings and the like.

Additional embodiments are described which achieve a cable-balancingconfiguration by inclusion of one or more inter-disk struts havingradial plugs which engage the adjacent disks (or disk and adjacentproximal or distal wrist portion). Alternative configurations of theintermediate strut and radial plugs may provide a nonattached connectionor an attached connection.

In certain embodiments, some of the cables are distal cables that extendfrom a proximal disk through at least one intermediate disk to aterminal connection to a distal disk. The remaining cables are medialcables that extend from the proximal disk to a terminal connection to amiddle disk. The cables are actuated by a cable actuator assemblyarranged to move each cable so as to deflect the wrist mechanism. In oneexemplary embodiment, the cable actuator assembly may include a gimbaledcable actuator plate. The actuator plate includes a plurality of smallradius holes or grooves for receiving the medial cables and a pluralityof large radius holes or grooves for receiving the distal cables. Theholes or grooves restrain the medial cables to a small radius of motion(e.g., ½ R) and the distal cables to a large radius of motion (R), sothat the medial cables to the medial disk move a smaller distance (e.g.,only half as far) compared to the distal cables to the distal disk, fora given gimbal motion or rotation relative to the particular cable. Notethat for alternative embodiments having more than one intermediate cabletermination segment, the cable actuator may have a plurality of sets ofholes at selected radii (e.g., R, ⅔ R, and ⅓ R). The wrist embodimentsdescribed are particularly suitable for robotic surgical systems,although they may be included in manually operated endoscopic tools.

Embodiments including a cable actuator assembly having aspects of theinvention provide to the simultaneous actuation of a substantialplurality of cables, and provide for a predetermined proportionality ofmotion of a plurality of distinct cable sets. This capability isprovided with a simple, inexpensive structure which avoids highlycomplex control mechanisms. As described further below, for a giventotal cross-sectional area in each cable set and a given overall diskdiameter, a mechanically redundant number of cables permits the cablediameter to be smaller, permits increasing the moment arm or mechanicaladvantage of the cables, and permits a larger unobstructed longitudinalcenter lumen along the centerline of the disks. These advantages areparticularly useful in wrist members built to achieve the very smalloverall diameter such as are currently used in endoscopic surgery.

In some embodiments, a grip actuation mechanism is provided foroperating a gripping end effector. When cables are used to manipulatethe end effector, the grip actuation mechanism may include a grip cableactuator disposed in a tool or instrument proximal base or “back end.”The path length of a grip actuation cable may tend to vary in lengthduring bending of the wrist in the event that cable paths do notcoincide with the neutral axis. The change in cable path lengths may beaccounted for in the back end mechanism used to secure and control thecables. This may be achieved by including a cable tension regulatingdevice in the grip actuation mechanism, so as to decouple the control ofthe end effector such as grip jaws from the bending of the wrist.

In specific embodiments, the back end mechanism is configured to allowfor the replacement of the end effector, the wrist, and the shaft of thesurgical instrument with relative ease.

In accordance with an aspect of the present invention, a minimallyinvasive surgical instrument comprises an elongate shaft having aworking end, a proximal end, and a shaft axis between the working endand the proximal end. A wrist member has a proximal portion connected tothe working end. An end effector is connected to a distal portion of thewrist member. The wrist member comprises at least three vertebraeconnected in series between the working end of the elongate shaft andthe end effector. The vertebrae include a proximal vertebra connected tothe working end of the elongate shaft and a distal vertebra connected tothe end effector.

Each vertebra is pivotable relative to an adjacent vertebra by a pivotalconnection, which may employ a nonattached (or alternatively anattached) contact. At least one of the vertebrae is pivotable relativeto an adjacent vertebra by a pitch contact around a pitch axis which isnonparallel to the shaft axis. At least one of the vertebrae ispivotable relative to an adjacent vertebra by another contact around asecond axis which is nonparallel to the shaft axis and nonparallel tothe pitch axis.

In accordance with another aspect of this invention, a minimallyinvasive surgical instrument comprises an elongate shaft having aworking end, a proximal end, and a shaft axis between the working endand the proximal end. A wrist member has a proximal portion or proximalend member connected to the working end, and a distal portion or distalend member connected to an end effector. The wrist member comprises atleast three vertebrae connected in series between the working end of theelongate shaft and an end effector.

The vertebrae include a proximal vertebra connected to the working endof the elongate shaft and a distal vertebra connected to the endeffector. Each vertebra is pivotable relative to an adjacent vertebra bya pivotable vertebral joint. At least one of the vertebrae is pivotablerelative to an adjacent vertebra by a pitch joint around a pitch axiswhich is nonparallel to the shaft axis. At least one of the vertebrae ispivotable relative to an adjacent vertebra by a yaw joint around a yawaxis which is nonparallel to the shaft axis and perpendicular to thepitch axis. An end effector is connected to a distal portion of thewrist member. A plurality of cables are coupled with the vertebrae tomove the vertebrae relative to each other. The plurality of cablesinclude at least one distal cable coupled with the terminating at thedistal vertebra and extending proximally to a cable actuator member, andat least one intermediate cable coupled with and terminating at anintermediate vertebra disposed between the proximal vertebra and thedistal vertebra and extending to the cable actuator member. The cableactuator member is configured to adjust positions of the vertebrae bymoving the distal cable by a distal displacement and the intermediatecable by an intermediate displacement shorter than the distaldisplacement.

In some embodiments, a ratio of each intermediate displacement to thedistal displacement is generally proportional to a ratio of a distancefrom the proximal vertebra to the intermediate vertebra to which theintermediate cable is connected and a distance from the proximalvertebra to the distal vertebra to which the distal cable is connected.

In accordance with another aspect of the invention, a method ofperforming minimally invasive endoscopic surgery in a body cavity of apatient comprises introducing an elongate shaft having a working endinto the cavity. The elongate shaft has a proximal end and a shaft axisbetween the working end and the proximal end. A wrist member comprisesat least three vertebrae connected in series between the working end ofthe elongate shaft and the end effector. The vertebrae include aproximal vertebra connected to the working end of the elongate shaft anda distal vertebra connected to the end effector. Each vertebra ispivotable relative to an adjacent vertebra by a pivotal coupling, whichmay employ a nonattached contact. An end effector is connected to adistal portion of the wrist member. The end effector is positioned byrotating the wrist member to pivot at least one vertebra relative to anadjacent vertebra by a pivotal pitch coupling around a pitch axis whichis nonparallel to the shaft axis. The end effector is repositioned byrotating the wrist member to pivot at least one vertebra relative to anadjacent vertebra by another pivotal coupling around a second axis whichis nonparallel to the shaft axis and nonparallel to the pitch axis.

In accordance with another aspect of the present invention, a minimallyinvasive surgical instrument has an end effector which comprises a gripsupport having a left pivot and a right pivot. A left jaw is rotatablearound the left pivot of the grip support and a right jaw is rotatablearound the right pivot of the grip support. A left slider pin isattached to the left jaw and spaced from the left pivot pin, and a rightslider pin is attached to the right jaw and spaced from the right pivotpin. A slotted member includes a left slider pin slot in which the leftslider pin is slidable to move the left jaw between an open position anda closed position, and a right slider pin slot in which the right sliderpin is slidable to move the right jaw between an open position and aclosed position. A slider pin actuator is movable relative to theslotted member to cause the left slider pin to slide in the left sliderpin slot and the right slider pin to slide in the right slider pin slot,to move the left jaw and the right jaw between the open position and theclosed position.

In accordance with another aspect of the present invention, a method ofperforming minimally invasive endoscopic surgery in a body cavity of apatient comprises providing a tool comprising an elongate shaft having aworking end coupled with an end effector, a proximal end, and a shaftaxis between the working end and the proximal end. The end effectorincludes a grip support having a left pivot and a right pivot; a leftjaw rotatable around the left pivot of the grip support and a right jawrotatable around the right pivot of the grip support, a left slider pinattached to the left jaw and spaced from the left pivot pin, a rightslider pin attached to the right jaw and spaced from the right pivotpin; and a slotted member including a left slider pin slot in which theleft slider pin is slidable to move the left jaw between an openposition and a closed position, and a right slider pin slot in which theright slider pin is slidable to move the right jaw between an openposition and a closed position. The method further comprises introducingthe end effector into a surgical site; and moving the left slider pin toslide in the left slider pin slot and the right slider pin to slide inthe right slider pin slot, to move the left jaw and the right jawbetween the open position and the closed position.

According to another aspect, a medical instrument comprises a base shafthaving a working end, a proximal end, and a shaft axis between theworking end and the proximal end. A segmented wrist member comprises aplurality of spaced-apart segment vertebrae disposed sequentiallyadjacent to one another along a wrist longitudinal line. The pluralityof vertebrae include a proximal vertebra connected to the shaft workingend, a distal vertebra supporting an end effector, and at least oneintermediate vertebra disposed between the proximal vertebra and thedistal vertebra, the at least one intermediate vertebrae being connectedto each adjacent vertebra by a pivotally movable segment coupling. Eachsegment coupling has a coupling axis nonparallel to the wristlongitudinal line. At least two of the coupling axes are non-parallel toone another. At least one of the intermediate vertebrae is a medialvertebra. A plurality of movable tendon elements are disposed generallylongitudinally with respect to the shaft and wrist member. The tendonelements each have a proximal portion, and have a distal portionconnected to one of the distal vertebra and the medial vertebra so as topivotally actuate the connected vertebra. At least one of the tendons isconnected to the at least one medial vertebra and at least one of thetendons is connected to the distal vertebra. A tendon actuationmechanism is drivingly coupled to the tendons and configured tocontrollably move at least selected ones of the plurality of tendons soas to pivotally actuate the plurality of connected vertebrae tolaterally bend the wrist member with respect to the shaft.

Another aspect is directed to a tendon actuating assembly for a surgicalinstrument, wherein the instrument includes a shaft-like member having adistal working end for insertion into a patient's body through anaperture, and wherein the working end includes at least one distalmoveable member arranged to be actuated by at least one of a pluralityof movable tendon element. The actuating assembly comprises a tendonactuator member which is configured to be movable to at least pivot inone degree of freedom, and which includes a plurality of tendonengagement portions. Each engagement portion is drivingly couplable toat least one of the plurality of tendons. A drive mechanism is drivinglycoupled to the actuator member so as to controllably pivot the actuatormember in the at least one degree of freedom, so as to move at least oneof the tendons relative to the shaft-like member so as to actuate thedistal moveable member.

In another aspect, a minimally invasive surgical instrument comprises ashaft having a working end, a proximal end, and a shaft axis between theworking end and the proximal end. A segmented wrist member comprises aplurality of spaced-apart segment vertebrae disposed sequentiallyadjacent to one another along a wrist longitudinal line. The pluralityof vertebrae include a proximal vertebra connected to the shaft workingend, a distal vertebra supporting an end effector, and at least oneintermediate vertebra disposed between the proximal vertebra and thedistal vertebra. The at least one intermediate vertebrae is connected toeach adjacent vertebra by a pivotally movable segment coupling. Eachsegment coupling has a coupling axis nonparallel to the wristlongitudinal line. At least two of the coupling axes are non-parallel toone another. The movable segment couplings include at least onespring-like element arranged to regulate the pivotal motion of at leastone adjacent vertebra. A plurality of movable tendon elements aredisposed generally longitudinally with respect to the shaft and wristmember. The tendon elements each have a proximal portion, and a distalportion connected to the distal vertebra so as to pivotally actuate thedistal vertebra. A tendon actuation mechanism is drivingly coupled tothe tendons and configured to controllably move at least one of theplurality of tendons so as to pivotally actuate the plurality ofconnected vertebrae to laterally bend the wrist member with respect tothe shaft.

Another aspect is directed a segment pivoted coupling mechanism forpivotally coupling two adjacent segment vertebrae of a multi-segmentflexible member of a medical instrument, wherein the two adjacentsegments have bending direction with respect to one another, and whereinthe flexible member has at least one neutral bending axis. Theinstrument includes at least two movable actuation tendon passingthrough at least two apertures in each adjacent vertebrae, wherein theat least two apertures in each of the vertebra are spaced apart onopposite sides of the neutral axis with respect to the pivot direction,and wherein openings of the apertures are disposed one adjacent surfacesof the two vertebrae so as to generally define an aperture plane. Thecoupling mechanism comprises at least one inter-vertebral engagementelement coupled to each of the vertebrae, the element pivotally engagingthe vertebrae so as to define at least two spaced-apart parallelcooperating pivot axes, each one of the pivot axes being alignedgenerally within the aperture plane of a respective one of the adjacentvertebra, so as to provide that each vertebra is pivotally movable aboutits respective pivot axis, so as to balance the motion of the tendons onopposite sides of the neutral axis when the flexible member is deflectedin the bending direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view schematically illustrating the rotation ofa gastroscope-style wrist;

FIG. 2 is an elevational view schematically illustrating an S-shapeconfiguration of the gastroscope-style wrist of FIG. 1;

FIG. 3 is an elevational view schematically illustrating agastroscope-style wrist having vertebrae connected by springs inaccordance with an embodiment of the present invention;

FIG. 4 is a partial cross-sectional view of a gastroscope-style wristhaving vertebrae connected by wave springs according to an embodiment ofthe invention;

FIG. 5 is a perspective view of a positively positionable multi-disk(PPMD) wrist in pitch rotation according to an embodiment of the presentinvention;

FIG. 6 is a perspective view of the PPMD wrist of FIG. 5 in yawrotation;

FIG. 7 is an elevational view of the PPMD wrist of FIG. 5 in a straightposition;

FIG. 8 is an elevational view of the PPMD wrist of FIG. 5 in pitchrotation;

FIG. 9 is a perspective view of a PPMD wrist in a straight positionaccording to another embodiment of the present invention;

FIG. 10 is a perspective view of the PPMD wrist of FIG. 9 in pitchrotation;

FIG. 11 is a perspective view of the PPMD wrist of FIG. 9 in yawrotation;

FIG. 12 is an upper perspective of an intermediate disk in the PPMDwrist of FIG. 9;

FIG. 13 is a lower perspective of the intermediate disk of FIG. 12;

FIG. 14 is a perspective view of a PPMD wrist in pitch rotation inaccordance with another embodiment of the present invention;

FIG. 15 is a perspective view of the PPMD wrist of FIG. 14 in yawrotation;

FIG. 16 is a perspective view of a PPMD wrist in pitch rotationaccording to another embodiment of the present invention;

FIG. 17 is a perspective view of a PPMD wrist in a straight position inaccordance with another embodiment of the present invention;

FIG. 18 is a perspective view of the PPMD wrist of FIG. 17 in pitchrotation;

FIG. 19 is an elevational view of the PPMD wrist of FIG. 17 in pitchrotation;

FIG. 20 is a perspective view of the PPMD wrist of FIG. 17 in yawrotation;

FIG. 21 is an elevational view of the PPMD wrist of FIG. 17 in yawrotation;

FIG. 22 is an elevational view of the PPMD wrist of FIG. 17 showing theactuation cables extending through the disks according to an embodimentof the invention;

FIG. 23 is an elevational view of the PPMD wrist of FIG. 17 in pitchrotation;

FIG. 24 is an elevational view of the PPMD wrist of FIG. 17 in yawrotation;

FIG. 25 is an cross-sectional view of the coupling between the disks ofthe PPMD wrist of FIG. 17 illustrating the rolling contact therebetween;

FIG. 26 is a perspective view of a gimbaled cable actuator according toan embodiment of the invention;

FIG. 27 is a perspective view of a gimbaled cable actuator with theactuator links configured in pitch rotation according to anotherembodiment of the present invention;

FIG. 28 is a perspective view of the gimbaled cable actuator of FIG. 27with the actuator links configured in yaw rotation;

FIG. 29 is another perspective view of the gimbaled cable actuator ofFIG. 27 in pitch rotation;

FIG. 30 is a perspective view of the parallel linkage in the gimbaledcable actuator of FIG. 27 illustrating details of the actuator plate;

FIG. 31 is a perspective view of the parallel linkage of FIG. 30illustrating the cover plate over the actuator plate;

FIG. 32 is another perspective view of the parallel linkage of FIG. 30illustrating details of the actuator plate;

FIG. 33 is a perspective view of the parallel linkage of FIG. 30illustrating the cover plate over the actuator plate and a mountingmember around the actuator plate for mounting the actuator links;

FIG. 34 is a perspective view of the gimbaled cable actuator of FIG. 27mounted on a lower housing member;

FIG. 35 is a perspective view of the gimbaled cable actuator of FIG. 27mounted between a lower housing member and an upper housing member;

FIG. 36 is a perspective view of a surgical instrument according to anembodiment of the present invention;

FIG. 37 is a perspective view of the wrist and end effector of thesurgical instrument of FIG. 36;

FIG. 38 is a partially cut-out perspective view of the wrist and endeffector of the surgical instrument of FIG. 36;

FIGS. 38A and 39 are additional partially cut-out perspective views ofthe wrist and end effector of the surgical instrument of FIG. 36;

FIGS. 39A and 39B are plan views illustrating the opening and closingactuators for the end effector of the surgical instrument of FIG. 36;

FIG. 39C is a perspective view of an end effector according to anotherembodiment;

FIG. 40 is the perspective view of FIG. 39 illustrating wrist controlcables;

FIG. 41 is an elevational view of the wrist and end effector of thesurgical instrument of FIG. 36;

FIG. 42 is a perspective view of a back end mechanism of the surgicalinstrument of FIG. 36 according to an embodiment of the presentinvention;

FIG. 43 is a perspective view of a lower member in the back endmechanism of FIG. 42 according to an embodiment of the presentinvention;

FIGS. 44-46 are perspective views of the back end mechanism according toanother embodiment of the present invention;

FIG. 47 is a perspective view of a mechanism for securing the actuationcables in the back end of the surgical instrument of FIGS. 44-46according to another embodiment of the present invention;

FIG. 48 is a perspective view of a back end mechanism of the surgicalinstrument of FIG. 36 according to another embodiment of the presentinvention;

FIGS. 49 and 50 are perspective views of a back end mechanism of thesurgical instrument of FIG. 36 according to another embodiment of thepresent invention;

FIG. 51 is a perspective of a PPMD wrist according to anotherembodiment;

FIG. 52 is an exploded view of a vertebra or disk segment in the PPMDwrist of FIG. 51;

FIGS. 53 and 54 are elevational views of the PPMD wrist of FIG. 51;

FIGS. 55 and 56 are perspective views illustrating the cable connectionsfor the PPMD wrist of FIG. 51;

FIGS. 57 and 58 are perspective views of a gimbaled cable actuatoraccording to another embodiment;

FIG. 59 is a perspective view of the gimbal plate of the actuator ofFIG. 55;

FIGS. 60-62 are exploded perspective views of the gimbaled cableactuator of FIG. 55;

FIG. 63 is another perspective view of the gimbaled cable actuator ofFIG. 55;

FIGS. 64-67 are perspective views of the back end according to anotherembodiment;

FIG. 68A is an elevational view of a straight wrist according to anotherembodiment;

FIG. 68B is an elevational view of a bent wrist; and

FIG. 68C is a schematic view of a cable actuator plate according toanother embodiment.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, “end effector” refers to an actual working distal partthat is manipulable by means of the wrist member for a medical function,e.g., for effecting a predetermined treatment of a target tissue. Forinstance, some end effectors have a single working member such as ascalpel, a blade, or an electrode. Other end effectors have a pair orplurality of working members such as forceps, graspers, scissors, orclip appliers, for example. In certain embodiments, the disks orvertebrae are configured to have openings which collectively define alongitudinal lumen or space along the wrist, providing a conduit for anyone of a number of alternative elements or instrumentalities associatedwith the operation of an end effector. Examples include conductors forelectrically activated end effectors (e.g., electrosurgical electrodes;transducers, sensors, and the like); conduits for fluids, gases orsolids (e.g., for suction, insufflation, irrigation, treatment fluids,accessory introduction, biopsy extraction and the like); mechanicalelements for actuating moving end effector members (e.g., cables,flexible elements or articulated elements for operating grips, forceps,scissors); wave guides; sonic conduction elements; fiberoptic elements;and the like. Such a longitudinal conduit may be provided with a liner,insulator or guide element such as a elastic polymer tube; spiral wirewound tube or the like.

As used herein, the terms “surgical instrument”, “instrument”, “surgicaltool”, or “tool” refer to a member having a working end which carriesone or more end effectors to be introduced into a surgical site in acavity of a patient, and is actuatable from outside the cavity tomanipulate the end effector(s) for effecting a desired treatment ormedical function of a target tissue in the surgical site. The instrumentor tool typically includes a shaft carrying the end effector(s) at adistal end, and is preferably servomechanically actuated by atelesurgical system for performing functions such as holding or drivinga needle, grasping a blood vessel, and dissecting tissue.

A. Gastroscope Style Wrist

A gastroscope style wrist has a plurality of vertebrae stacked one ontop of another with alternating yaw (Y) and pitch (P) axes. Forinstance, an example of a gastroscope-style wrist may include twelvevertebrae. Such a wrist typically bends in a relatively long arc. Thevertebrae are held together and manipulated by a plurality of cables.The use of four or more cables allows the angle of one end of the wristto be determined when moved with respect to the other end of the wrist.Accessories can be conveniently delivered through the middle opening ofthe wrist. The wrist can be articulated to move continuously to haveorientation in a wide range of angles (in roll, pitch, and yaw) withgood control and no singularity.

FIGS. 1 and 2 show a typical prior art gastroscope style flexiblewrist-like multi-segment member having a plurality of vertebrae or diskscoupled in series in alternating yaw and pitch pivotal arrangement (YPYP. . . Y). FIG. 1 shows the rotation of a gastroscope-style wrist 40having vertebrae 42, preferably rotating at generally uniform anglesbetween neighboring vertebrae 42. On the other hand, when pitch and yawforces are applied, the gastroscope-style wrist can take on an S shapewith two arcs, as seen in FIG. 2. In addition, backlash can be a problemwhen the angles between neighboring vertebrae vary widely along thestack. It may be seen that, in operation, the angles of yaw and pitchbetween adjacent segments may typically take a range of non-uniform, orindeterminate values during bending. Thus, a multi-segment wrist orflexible member may exhibit unpredictable or only partially controlledbehavior in response to tendon actuation inputs. Among other things,this can reduce the bending precision, repeatability and useful strengthof the flexible member.

One way to minimize backlash and avoid the S-shape configuration is toprovide springs 54 between the vertebrae 52 of the wrist 50, asschematically illustrated in FIG. 3. The springs 54 help keep the anglesbetween the vertebrae 52 relatively uniform during rotation of the stackto minimize backlash. The springs 54 also stiffen the wrist 50 andstabilize the rotation to avoid the S-shape configuration.

As shown in the wrist 60 of FIG. 4, one type of spring that can beconnected between the vertebrae 62 is a wave spring 64, which has thefeature of providing a high spring force at a low profile. FIG. 4 alsoshows an end effector in the form of a scissor or forcep mechanism 66.Actuation members such as cables or pulleys for actuating the mechanism66 may conveniently extend through the middle opening of the wrist 60.The middle opening or lumen allows other items to be passedtherethrough.

The wrist 60 is singularity free, and can be designed to bend as much as360° if desired. The wrist 60 is versatile, and can be used forirrigation, imaging with either fiberoptics or the wires to a CCDpassing through the lumen, and the like. The wrist 60 may be used as adelivery device with a working channel. For instance, the surgicalinstrument with the wrist 60 can be positioned by the surgeon, andhand-operated catheter-style or gastroenterology instruments can bedelivered to the surgical site through the working channel for biopsies.

Note that in FIGS. 1-4, (and generally elsewhere herein) the distinctionbetween yaw and pitch may be arbitrary as terms of generalizeddescription of a multi-segment wrist or flexible member, the Y and Paxes typically being generally perpendicular to a longitudinalcenterline of the member and also typically generally perpendicular toeach other. Note, however, that various alternative embodiments havingaspects of the invention are feasible having Y and P axes which are notgenerally perpendicular to a centerline and/or not generallyperpendicular to one another. Likewise, a simplified member may beuseful while having only a single degree of freedom in bending motion (Yor P).

B. Positively Positionable Multi-Disk Wrist (PPMD Wrist)

A constant velocity or PPMD wrist also has a plurality of vertebrae ordisks stacked one on top of another in a series of pivotally coupledengagements and manipulated by cables. In one five-disk embodiment (thedisk count including end members), to prevent the S-shape configuration,one set of the cables (distal cables) extend to and terminate at thelast vertebrae or distal end disk at the distal end of the wrist, whilethe remaining set of cables (medial cables) extend to and terminate at amiddle disk. By terminating a medial set of cables at the medial disk,and terminating second distal set of cables at the distal disk, allpivotal degrees of freedom of the five disk sequence may bedeterminately controlled by cable actuators. There is no substantialuncertainty of wrist member shape or position for any given combinationof cable actuations. This is the property implied by the term“positively positionable”, and which eliminates the cause of S-curvebending or unpredictable bending as described above with respect toFIGS. 1-2).

Note that medial cable set of the PPMD wrist will move a shorterdistance than the distal set, for a given overall wrist motion (e.g.,half as far). The cable actuator mechanism, examples of which aredescribed further below, provides for this differential motion. Notealso, that while the examples shown generally include a plurality ofdisks or segments which are similarly or identically sized, they neednot be. Thus, where adjacent segments have different sizes, the scale ofmotion between the medial set(s) and the distal set may differ from theexamples shown.

In certain preferred embodiments, one of a yaw (Y) or pitch (P) couplingis repeated in two consecutive segments. Thus, for the an exemplarysequence of four couplings between the 5 disk segments, the couplingsequence may be YPPY or PYYP, and medial segment disk (number 3 of 5) isbounded by two Y or two P couplings. This arrangement has the propertythat permits a “constant velocity” rolling motion in a “roll, pitch,yaw” type instrument distal end. In other words, in the event that theinstrument distal portion (shaft/wrist/end effector) is rotated axiallyabout the centerline while the wrist is bent and while the end effectoris maintained at a given location and pointing angle (analogous to theoperation of a flexible-shaft screw driver), both end effector andinstrument shaft will rotate at the same instantaneous angular velocity.

This property “constant velocity” may simplify control algorithms for adexterous surgical manipulation instrument, and produce smootheroperation characteristics. Note that this coupling sequence is quitedistinct from the alternating YPYP . . . coupling arrangement of theprior art gastroscope style wrist shown in FIGS. 1 and 2, which includesa strictly alternating sequence of yaw and pitch axes.

In an exemplary embodiment shown in FIGS. 5-8, the wrist 70 has fivedisks 72-76 stacked with pitch, yaw, yaw, and pitch joints (the diskcount including proximal and distal end member disks). The disks areannular and form a hollow center or lumen. Each disk has a plurality ofapertures 78 for passing through actuation cables. To lower the forceson each cable, sixteen cables are used. Eight distal cables 80 extend tothe fifth disk 76 at the distal end; and eight medial cables 82 extendto the third disk 74 in the middle. The number of cables may change inother embodiments, although a minimum of three cables (or four in asymmetrical arrangement), more desirably six or eight cables, are used.The number and size of cables are limited by the space available aroundthe disks. In one embodiment, the inner diameter of each disk is about 3mm, the outer diameter is about 2 mm, and the apertures for passingthrough the cables are about 0.5 mm in diameter. For a given totalcross-sectional area in each cable set (medial or distal) and a givenoverall disk diameter, a mechanically redundant number of cables permitsthe cable diameter to be smaller, and thus permits the cables toterminate at apertures positioned farther outward radially from thecenter line of the medial or distal disk, thus increasing the moment armor mechanical advantage of applied cable forces. In addition, theresulting smaller cable diameter permits a larger unobstructedlongitudinal center lumen along the centerline of the disks. Theseadvantages are particularly useful in wrist members built to achieve thevery small overall diameter of the insertable instrument portion (about5 mm or less) that is currently favored for the endoscopic surgery.

FIG. 5 shows alternating pairs of long or distal cables 80 and short ormedial cable 82 disposed around the disks. The cables 80, 82 extendingthrough the disks are parallel to a wrist central axis or neutral axis83 extending through the centers of the disks. The wrist neutral axis 83is fixed in length during bending of the wrist 70. When the disks arealigned in a straight line, the cables 80, 82 are straight; when thedisks are rotated during bending of the wrist 70, the cables 80, 82 bendwith the wrist neutral axis. In the examples shown in FIGS. 5-8, thedisks are configured to roll on each other in nonattached, rollingcontact to maintain the contact points between adjacent disks in thecenter, as formed by pairs of pins 86 coupled to apertures 78 disposedon opposite sides of the disks. The pins 86 are configured and sizedsuch that they provide the full range of rotation between the disks andstay coupled to the apertures 78. The apertures 78 may be replaced byslots for receiving the pins 86 in other embodiments. Note that thecontour of pins 86 is preferably of a “gear tooth-like” profile, so asto make constant smooth contact with the perimeter 87 of its engagedaperture during disk rotation, so as to provide a smooth non-sliprolling engagement. FIGS. 5 and 8 show the wrist 70 in a 90° pitchposition (by rotation of the two pitch joints), while FIG. 6 shows thewrist 70 in a 90° yaw position (by rotation of the two yaw joints). InFIG. 7, the wrist 70 is in an upright or straight position. Of course,combined pitch and yaw bending of the wrist member can be achieved byrotation of the disks both in pitch and in yaw.

The wrist 70 is singularity free over a 180° range. The lumen formed bythe annular disks can be used for isolation and for passing pull cablesfor grip. The force applied to the wrist 70 is limited by the strengthof the cables. In one embodiment, a cable tension of about 15 lb. isneeded for a yaw moment of about 0.25 N-m. Because there are only fivedisks, the grip mechanism needs to be able to bend sharply. Precision ofthe cable system depends on the friction of the cables rubbing on theapertures 78. The cables 80, 82 can be preloaded to remove backlash.Because wear is a concern, wear-resistant materials should desirably beselected for the wrist 70 and cables.

FIGS. 9-13 show an alternative embodiment of a wrist 90 having adifferent coupling mechanism between the disks 92-96 which includeapertures 98 for passing through actuation cables. Instead of pinscoupled with apertures, the disks are connected by a coupling betweenpairs of curved protrusions 100 and slots 102 disposed on opposite sidesof the disks, as best seen in the disk 94 of FIGS. 12-13. The other twointermediate disks 93, 95 are similar to the middle disk 94. The curvedprotrusions 100 are received by the curved slots 102 which support theprotrusions 100 for rotational or rolling movement relative to the slots102 to generate, for instance, the 90° pitch of the wrist 90 as shown inFIG. 10 and the 90° yaw of the wrist 90 as shown in FIG. 11. FIG. 9shows two distal cables 104 extending to and terminating at the distaldisk 96, and two medial cables 106 extending to and terminating at themiddle disk 94. Note that the example shown in FIGS. 9-13 is not a“constant velocity” YPPY arrangement, but may alternatively be soconfigured.

In another embodiment of the wrist 120 as shown in FIGS. 14 and 15, thecoupling between the disks 122-126 is formed by nonattached, rollingcontact between matching gear teeth 130 disposed on opposite sides ofthe disks. The gear teeth 130 guide the disks in yaw and pitch rotationsto produce, for instance, the 90° pitch of the wrist 120 as shown inFIG. 14 and the 90° yaw of the wrist 120 as shown in FIG. 15.

In another embodiment of the wrist 140 as illustrated in FIG. 16, thecoupling mechanism between the disks includes apertured members 150, 152cooperating with one another to permit insertion of a fastener throughthe apertures to form a hinge mechanism. The hinge mechanisms disposedon opposite sides of the disks guide the disks in pitch and yawrotations to produce, for instance, the 90° pitch of the wrist 140 asseen in FIG. 16. Note that the example shown in FIG. 16 is not a“constant velocity” YPPY arrangement, but may alternatively be soconfigured.

FIGS. 17-24 show yet another embodiment of the wrist 160 having adifferent coupling mechanism between the disks 162-166. The first orproximal disk 162 includes a pair of pitch protrusions 170 disposed onopposite sides about 180° apart. The second disk includes a pair ofmatching pitch protrusions 172 coupled with the pair of pitchprotrusions 170 on one side, and on the other side a pair of yawprotrusions 174 disposed about 90° offset from the pitch protrusions172. The third or middle disk 164 includes a pair of matching yawprotrusions 176 coupled with the pair of yaw protrusions 174 on oneside, and on the other side a pair of yaw protrusions 178 aligned withthe pair of yaw protrusions 174. The fourth disk 165 includes a pair ofmatching yaw protrusions 180 coupled with the pair of yaw protrusions178 on one side, and on the other side a pair of pitch protrusions 182disposed about 90° offset from the yaw protrusions 180. The fifth ordistal disk 166 includes a pair of matching pitch protrusions 184coupled with the pitch protrusions 182 of the fourth disk 165.

The protrusions 172 and 176 having curved, convex rolling surfaces thatmake nonattached, rolling contact with each other to guide the disks inpitch or yaw rotations to produce, for instance, the 90° pitch of thewrist 160 as seen in FIGS. 18 and 19 and the 90° yaw of the wrist 160 asseen in FIGS. 20 and 21. In the embodiment shown, the coupling betweenthe protrusions is each formed by a pin 190 connected to a slot 192.

FIGS. 22-24 illustrate the wrist 160 manipulated by actuation cables toachieve a straight position, a 90° pitch position, and a 90° yawposition, respectively.

FIG. 25 illustrates the rolling contact between the curved rollingsurfaces of protrusions 170, 172 for disks 162, 163, which maintaincontact at a rolling contact point 200. The rolling action implies twovirtual pivot points 202, 204 on the two disks 162, 163, respectively.The relative rotation between the disks 162, 163 is achieved by pullingcables 212, 214, 216, 218. Each pair of cables (212, 218) and (214, 216)are equidistant from the center line 220 that passes through the contactpoint 200 and the virtual pivot points 202, 204. Upon rotation of thedisks 162, 163, the pulling cables shift to positions 212′, 214′, 216′,218′, as shown in broken lines. The disk 162 has cable exit points 222for the cables, and the disk 163 has cable exit points 224 for thecables. In a specific embodiment, the cable exit points 222 are coplanarwith the virtual pivot point 202 of the disk 162, and the cable exitpoints 224 are coplanar with the virtual pivot point 204 of the disk164. In this way, upon rotation of the disks 162, 163, each pair ofcables (212′, 218′) and (214′, 216′) are kept equidistant from thecenter line 220. As a result, the cable length paid out on one side isequal to the cable length pulled on the other side. Thus, thenon-attached, rolling engagement contour arrangement shown in FIG. 25may be referred to as a “cable balancing pivotal mechanism.” This “cablebalancing” property facilitates coupling of pairs of cables with minimalbacklash. Note that the example of FIGS. 17-24 has this “cablebalancing” property, although due to the size of these figures, theengagement rolling contours are shown at a small scale.

Optionally, and particularly in embodiments not employing a “cablebalancing pivotal mechanism” to couple adjacent disks, the instrumentcable actuator(s) may employ a cable tension regulation device to takeup cable slack or backlash. The above embodiments show five disks, butthe number of disks may be increased to seven, nine, etc. For aseven-disk wrist, the range of rotation increases from 180° to 270°.Thus, in a seven-disk wrist, typically ⅓ of the cables terminate at disk3; ⅓ terminate at disk 5; and ⅓ terminate at disk 7 (most distal).

C. Pivoted Plate Cable Actuator Mechanism

FIG. 26 shows an exemplary pivoted plate cable actuator mechanism 240having aspects of the invention, for manipulating the cables, forinstance, in the PPMD wrist 160 shown in FIGS. 17-21. The actuator 240includes a base 242 having a pair of gimbal ring supports 244 withpivots 245 for supporting a gimbal ring 246 for rotation, for example,in pitch. The ring 246 includes pivots 247 for supporting a rocker oractuator plate 250 in rotation, for example, in yaw. The actuator plate250 includes sixteen holes 252 for passing through sixteen cables formanipulating the wrist 160 (from the proximal disk 162, eight distalcables extend to the distal disk 166 and eight medial cables extend tothe middle disk 164).

The actuator plate 250 includes a central aperture 256 having aplurality of grooves for receiving the cables. There are eight smallradius grooves 258 and eight large radius grooves 260 distributed inpairs around the central aperture 256. The small radius grooves receivemedial cables that extend to the middle disk 164, while the large radiusgrooves receive distal cables that extend to the distal disk 166. Thelarge radius for grooves 260 is equal to about twice the small radiusfor grooves 258. The cables are led to the rim of the central aperture256 through the grooves 258, 260 which restrain half of the cables to asmall radius of motion and half of the cables to a large radius ofmotion, so that the medial cables to the medial disk 164 move only halfas far as the distal cables to the distal disk 166, for a given gimbalmotion. The dual radius groove arrangement facilitates such motion andcontrol of the cables when the actuator plate 250 is rotated in thegimbaled cable actuator 240. A pair of set screws 266 are desirablyprovided to fix the cable attachment after pre-tensioning. The gimbaledcable actuator 240 acts as a master for manipulating and controllingmovement of the slave PPMD wrist 160. Various kinds of conventionalactuator (not shown in FIG. 26) may be coupled to actuator plateassembly to controllably tilt the plate in two degrees of freedom toactuate to cables.

FIGS. 27-35 illustrate another embodiment of a gimbaled cable actuator300 for manipulating the cables to control movement of the PPMD wrist,in which an articulated parallel strut/ball joint assembly is employedto provide a “gimbaled” support for actuator plate 302 (i.e., the plateis supported so as to permit plate tilting in two DOF). The actuatorincludes a rocker or actuator plate 302 mounted in a gimbalconfiguration. The actuator plate 302 is moved by a first actuator link304 and a second actuator link 306 to produce pitch and yaw rotations.The actuator links 304, 306 are rotatably coupled to a mounting memberdisposed around the actuator plate 302. As best seen in FIG. 33, ballends 310 are used for coupling the actuator links 304, 306 with themounting member 308 to form ball-in-socket joints in the specificembodiment shown, but other suitable rotational connections may be usedin alternate embodiments. The actuator links 304, 306 are driven to movegenerally longitudinally by first and second follower gear quadrants314, 316, respectively, which are rotatably coupled with the actuatorlinks 304, 306 via pivot joints 318, 320, as shown in FIGS. 27 and 28.The gear quadrants 314, 316 are rotated by first and second drive gears324, 326, respectively, which are in turn actuated by drive spools 334,336, as best seen in FIGS. 34 and 35.

The actuator plate 302 is coupled to a parallel linkage 340 asillustrated in FIGS. 30-33. The parallel linkage 340 includes a pair ofparallel links 342 coupled to a pair of parallel rings 344 which form aparallelogram in a plane during movement of the parallel linkage 340.The pair of parallel links 342 are rotatably connected to the pair ofparallel rings 344, which are in turn rotatably connected to a parallellinkage housing 346 via pivots 348 to rotate in pitch. The pair ofparallel links 342 may be coupled to the actuator plate 302 viaball-in-socket joints 349, as best seen in FIG. 32, although othersuitable coupling mechanisms may be used in alternate embodiments.

FIGS. 27 and 29 show the actuator plate 302 of the gimbaled cableactuator 300 in pitch rotation with both actuator links 304, 306 movingtogether so that the actuator plate 302 is constrained by the parallellinkage 340 to move in pitch rotation. In FIG. 28, the first and secondactuator links 304, 306 move in opposite directions to produce a yawrotation of the actuator plate 302. Mixed pitch and yaw rotations resultfrom adjusting the mixed movement of the actuator links 304, 306.

As best seen in FIGS. 30 and 32, the actuator plate 302 includes eightsmall radius apertures 360 for receiving medial cables and eight largeradius apertures 362 for receiving distal cables. FIG. 32 shows a medialcable 364 for illustrative purposes. The medial and distal actuationcables extend through the hollow center of the parallel linkage housing346 and the hollow center of the shaft 370 (FIGS. 27 and 28), forinstance, to the middle and distal disks 164, 166 of the PPMD wrist 160of FIGS. 17-21.

FIG. 34 shows the gimbaled cable actuator 300 mounted on a lower housingmember 380. FIG. 35 shows an upper housing member 382 mounted on thelower housing member 380. The upper housing member 382 includes pivots384 for rotatably mounting the gear quadrants 314, 316. A cover plate390 may be mounted over the actuator plate 302 by fasteners 392, as seenin FIGS. 27, 28, 31, 33, and 34.

Note that the most distal disk (e.g., disk 166 in FIGS. 17-21) may serveas a mounting base for various kinds of single-element and multi-elementend effectors, such as scalpels, forceps, scissors, cautery tools,retractors, and the like. The central lumen internal to the disks mayserve as a conduit for end-effector actuator elements (e.g., endeffector actuator cables), and may also house fluid conduits (e.g.,irrigation or suction) or electrical conductors.

Note that although gimbal ring support assembly 240 is shown in FIG. 26for actuator plate 250, and an articulated gimbal-like structure 300 isshown in FIGS. 27-35 for actuator plate 302, alternative embodiments ofthe pivoted-plate cable actuator mechanism having aspects of theinvention may have different structures and arrangements for supportingand controllably moving the actuator plate 250. For example the platemay be supported and moved by various types of mechanisms andarticulated linkages to permit at least tilting motion in two DOF, forexample a Stewart platform and the like. The plate assembly may becontrollably actuated by a variety of alternative drive mechanisms, suchas motor-driven linkages, hydraulic actuators; electromechanicalactuators, linear motors, magnetically coupled drives and the like.

D. Grip Actuation Mechanism

FIG. 36 shows a surgical instrument 400 having an elongate shaft 402 anda wrist-like mechanism 404 with an end effector 406 located at a workingend of the shaft 402. The wrist-like mechanism 404 shown is similar tothe PPMD wrist 160 of FIGS. 17-21. The PPMD wrist has a lot of smallcavities and crevices. For maintaining sterility, a sheath 408A may beplaced over the wrist 404. Alternatively, a sheath 408B may be providedto cover the end effector 406 and the wrist 404.

A back end or instrument manipulating mechanism 410 is located at anopposed end of the shaft 402, and is arranged releasably to couple theinstrument 400 to a robotic arm or system. The robotic arm is used tomanipulate the back end mechanism 410 to operate the wrist-likemechanism 404 and the end effector 406. Examples of such robotic systemsare found in various related applications as listed above, such as PCTInternational Application No. PCT/US98/19508, entitled “RoboticApparatus”, filed on Sep. 18, 1998, and published as WO99/50721; andU.S. patent application Ser. No. 09/398,958, entitled “Surgical Toolsfor Use in Minimally Invasive Telesurgical Applications”, filed on Sep.17, 1999. In some embodiments, the shaft 402 is rotatably coupled to theback end mechanism to enable angular displacement of the shaft 402relative to the back end mechanism 410 as indicated by arrows H.

The wrist-like mechanism 404 and end effector 406 are shown in greaterdetail in FIGS. 27-41. The wrist-like mechanism 404 is similar to thePPMD wrist 160 of FIGS. 17-21, and includes a first or proximal disk 412connected to the distal end of the shaft 402, a second disk 413, a thirdor middle disk 414, a fourth disk 415, and a fifth or distal disk 416. Agrip support 420 is connected between the distal disk 416 and the endeffector 406, which includes a pair of working members or jaws 422, 424.To facilitate grip movement, the jaws 422, 424 are rotatably supportedby the grip support 420 to rotate around pivot pins 426, 428,respectively, as best seen in FIGS. 38-40. Of course, other endeffectors may be used. The jaws 422, 424 shown are merely illustrative.

The grip movement is produced by a pair of slider pins 432, 434connected to the jaws 422, 424, respectively, an opening actuator 436,and a closing actuator 438, which are best seen in FIGS. 38-40. Theslider pins 432, 434 are slidable in a pair of slots 442, 444,respectively, provided in the closing actuator 438. When the slider pins432, 434 slide apart outward along the slots 442, 444, the jaws 422, 424open in rotation around the pivot pins 426, 428. When the slider pins432, 434 slide inward along the slots 442, 444 toward one another, thejaws 422, 424 close in rotation around the pivot pins 426, 428. Thesliding movement of the slider pins 432, 434 is generated by theircontact with the opening actuator as it moves relative to the closingactuator 438. The opening actuator 436 acts as a cam on the slider pins432, 434. The closing of the jaws 422, 424 is produced by pulling theclosing actuator 438 back toward the shaft 402 relative to the openingactuator 436 using a closing actuator cable 448, as shown in FIG. 39A.The opening of the jaws 422, 424 is produced by pulling the openingactuator 436 back toward the shaft 402 relative to the closing actuator438 using an opening actuator cable 446, as shown in FIG. 39B. Theopening actuator cable 446 is typically crimped into the hollow tail ofthe opening actuator 436, and the closing actuator cable 448 istypically crimped into the hollow tail of the closing actuator 438. In aspecific embodiment, the opening actuator cable 446 and the closingactuator cable 448 are moved in conjunction with one another, so thatthe opening actuator and the closing actuator 438 move simultaneously atan equal rate, but in opposite directions. The actuation cables 446, 448are manipulated at the back end mechanism 410, as described in moredetail below. The closing actuator 438 is a slotted member and theclosing actuator cable 446 may be referred to as the slotted membercable. The opening actuator 436 is a slider pin actuator and the openingactuator cable 448 may be referred to as the slider pin actuator cable.

To ensure that the grip members or jaws 422′, 424′ move symmetrically,an interlocking tooth mechanism 449 may be employed, as illustrated inFIG. 39C. The mechanism 449 includes a tooth provided on the proximalportion of one jaw 424′ rotatably coupled to a slot or groove providedin the proximal portion of the other jaw 424′. The mechanism 449includes another interlocking tooth and slot on the opposite side (notshown) of the jaws 422′, 424′.

A plurality of long or distal cables and a plurality of short or medialcables, similar to those shown in FIG. 5, are used to manipulate thewrist 404. FIG. 40 shows one distal cable and one medial cable 454 forillustrative purposes. Each cable (452, 454) extends through adjacentsets of apertures with free ends extending proximally through the toolshaft 402, and makes two passes through the length of the wrist 404.There are desirably a total of four distal cables and four medial cablesalternatively arranged around the disks 412-416. The actuation cables446, 448 and the wrist control cables such as 452, 454 pass through thelumen formed by the annular disks 412-416 back through the shaft 402 tothe back end mechanism 410, where these cables are manipulated. In someembodiments, a conduit 450 is provided in the lumen formed by theannular disks 412-416 (see FIG. 39) to minimize or reduce cable snaggingor the like. In a specific embodiment, the conduit 450 is formed by acoil spring connected between the proximal disk 412 and the distal disk416. The coil spring bends with the disks 412-416 without interferingwith the movement of the disks 412-416.

The grip support 420 may be fastened to the wrist 404 using any suitablemethod. In one embodiment, the grip support 420 is held tightly to thewrist 404 by support cables 462, 464, as illustrated in FIGS. 38 and38A. Each support cable extends through a pair of adjacent holes in thegrip support 420 toward the wrist 404. The support cables 462, 464 alsopass through the lumen formed by the annular disks 412-416 back throughthe shaft 402 to the back end mechanism 410, where they are secured.

Referring to FIG. 41, the wrist 404 has a wrist central axis or neutralaxis 470 that is fixed in length during bending of the wrist 404. Thevarious cables, however, vary in length during bending of the wrist 404as they take on cable paths that do not coincide with the neutral axis,such as the cable path 472 shown. Constraining the cables to bendsubstantially along the neutral axis 470 (e.g., by squeezing down thespace in the wrist 404) reduces the variation in cable lengths, but willtend to introduce excessive wear problems. In some embodiments, thechange in cable lengths will be accounted for in the back end mechanism410, as described below.

FIGS. 42-46 show a back end mechanism 410 according to an embodiment ofthe present invention. One feature of this embodiment of the back endmechanism 410 is that it allows for the replacement of the end effector406 (e.g., the working members or jaws 422, 424, the actuators 436, 438,and the actuation cables 446, 448) with relative ease.

As shown in FIG. 42, the support cables 462, 464 (see FIGS. 38 and 38A)used to hold the grip support 420 to the wrist 404 extend through acentral tube after passing through the shaft 402. The support cables462, 464 are clamped to a lower arm 480 and lower clamp block 482 whichare screwed tight. The lower arm 480 includes a pivot end 486 and aspring attachment end 488. The pivot end 486 is rotatably mounted to theback end housing or structure 490, as shown in FIG. 42. The springattachment end 488 is connected to a spring which is fixed to the backend housing 490. The spring 492 biases the lower arm 480 to applytension to the support cables 462, 464 to hold the grip support 420tightly to the wrist 404.

FIG. 43 shows another way to secure the support cables 462, 464 by usingfour recesses or slots 484 in the lower arm 480 instead of the clampblock 482. A sleeve is crimped onto each of the ends of the supportcables 462, 464, and the sleeves are tucked into the recesses or slots484. This is done by pushing the lower arm 480 inward against the springforce, and slipping the sleeved cables into their slots.

FIG. 44 shows an additional mechanism that allows the lengths of theactuation cables 446, 448 (see FIG. 39) to change without affecting theposition of the grip jaws 422, 424. The actuation cables 446, 448extending through the shaft 402 are clamped to a grip actuation pivotingshaft 500 at opposite sides of the actuation cable clamping member 502with respect to the pivoting shaft 500. The clamping member 502 rotateswith the grip actuation pivoting shaft 500 so as to pull one actuationcable while simultaneously releasing the other to operate the jaws 422,424 of the end effector 406.

Instead of the clamping member 502 for clamping the actuation cables446, 448, a different cable securing member 502′ may be used for thegrip actuation pivot shaft 500, as shown in FIG. 47. The cable securingmember 502′ includes a pair of oppositely disposed recesses or slots504. A sleeve is crimped onto each of the ends of the actuation cables446, 448, and the sleeves are tucked into the recesses or slots 504.This is done by pushing the upper arm 530 inward against the springforce, and slipping the sleeved cables into their slots.

As shown in FIGS. 44-46, the grip actuation pivot shaft 500 iscontrolled by a pair of control cables 506, 508 that are connected tothe motor input shaft 510. The two control cables 506, 508 are clampedto the grip actuation pivot shaft 500 by two hub clamps 512, 514,respectively. From the hub clamps 512, 514, the control cables 506, 508travel to two helical gear reduction idler pulleys 516, 518, and then tothe motor input shaft 510, where they are secured by two additional hubclamps 522, 524. As shown in FIG. 44, the two control cables 506, 508are oppositely wound to provide the proper torque transfer in bothclockwise and counterclockwise directions. Rotation of the motor inputshaft 510 twists the grip actuation pivot shaft 500 via the controlcables 506, 508, which in turn pulls one actuation cable whilesimultaneously releasing the other, thereby actuating the jaws 422, 424of the end effector 406.

The grip actuation pivot shaft 500 and the pair of helical gearreduction idler pulleys 516, 518 are pivotally supported by a link box520. The link box 520 is connected to a link beam 522, which ispivotally supported along the axis of the motor input shaft 510 to allowthe grip actuation pivot shaft 500 to move back and forth to account forchange in cable length due to bending of the wrist 404, without changingthe relative position of the two actuation cables 446, 448 that controlthe grip jaws 422, 424. This feature decouples the control of the gripjaws 422, 424 from the bending of the wrist 404.

FIGS. 45 and 46 show the addition of an upper arm 530 which is similarto the lower arm 480. The upper arm 530 also has a pivot end 536 and aspring attachment end 538. The pivot end 536 is rotatably mounted to theback end housing 490 along the same pivot axis as the pivot end 486 ofthe lower arm 480. The upper arm 530 is connected to the grip actuationpivot shaft 500. The spring attachment end 538 is connected to a spring542 which is fixed to the back end housing 490. The spring 542 biasesthe upper arm 530 to apply a pretension to the actuation cables 446,448. The springs 492, 542 are not shown in FIG. 46 for simplicity andclarity.

The configuration of the back end mechanism 410 facilitates relativelyeasy replacement of the actuators 436, 438 and actuation cables 446,448, as well as the working members or jaws 422, 424. The cables can bereleased from the back end mechanism 410 with relative ease,particularly when the cables are secured to recesses by crimped sleeves(see FIGS. 43, 47).

In another embodiment of the back end mechanism 410A as shown in FIG.48, not only the end effector 406 but the wrist 404 and the shaft 402may also be replaced with relative ease. As shown in FIGS. 27-35 anddescribed above, the wrist cables (e.g., the distal cable 452 and medialcable 454 in FIG. 40) for actuating the wrist 404 all terminate at theback end on a circular ring of the actuator plate 302. The wrist cablesare clamped to the actuator plate 302 with a cover plate 390 (see FIGS.27-35).

To achieve the replaceable scheme of the wrist 404 and shaft 402, thewrist cables are fastened to a smaller plate (e.g., by clamping), andthe smaller plate is fed from the instrument from the front 550 of theback end housing 490 and affixed to the actuator plate 302.

In an alternate configuration, the actuator plate 302 may berepositioned to the front of the back end housing 490 to eliminate theneed to thread the smaller plate through the length of the shaft 402.

FIGS. 49 and 50 show another back end mechanism 410B illustratinganother way of securing the cables. The support cables 462, 464 (seeFIGS. 38 and 38A) are clamped to the arm 560 by a clamping block 562.The arm 560 has a pivot end 564 and a spring attachment end 566. Thepivot end 564 is rotatably mounted to the back end housing or structure490. The spring attachment end 566 is connected to one or more springs570 which are fixed to the back end housing 490. The springs 570 biasthe arm 560 to apply tension to the support cables 462, 464 to hold thegrip support 420 tightly to the wrist 404.

The actuation cables 446, 448 (see FIG. 39) extend around pulleys 580connected to the arm 560, and terminate at a pair of hub clamps 582, 584provided along the motor input shaft 590. This relatively simplearrangement achieves the accommodation of cable length changes andpretensioning of the cables. The support cables 462, 464 are tensionedby the springs 570. The actuation cables 446, 448 are tensioned byapplying a torque to the hub clamps 582, 584. The replacement of the endeffector 406 and wrist 404 will be more difficult than some of theembodiments described above.

E. A More Compact Embodiment

FIGS. 51-67 illustrate another PPMD wrist tool that is designed to havecertain components that are more compact or easier to manufacture orassemble. As shown in FIGS. 51-56, the PPMD wrist 600 connected betweena tool shaft 602 and an end effector 604. The wrist 600 includes eightnested disk segments 611-618 that are preferably identical, whichimproves manufacturing efficiency and cost-effectiveness. An individualdisk segment 610 is seen in FIG. 52. Four struts 620 are provided, eachof which is used to connect a pair of disk segments together. Anindividual strut 620 is shown in FIG. 52.

The disk segment 610 includes a mating side having a plurality of matingextensions extending in the axial direction (four mating extensionsspaced around the circumference in a specific embodiment), and apivoting side having a gear tooth 624 and a gear slot 626. The geartooth 624 and gear slot 626 are disposed on opposite sides relative to acenter opening 628. Twelve apertures 630 are distributed around thecircumference of the disk segment 610 to receive cables for wristactuation, as described in more detail below. The disk segment 610further includes a pair of radial grooves or slots 632 disposed onopposite sides relative to the center opening 628. In the specificembodiment shown, the radial grooves 632 are aligned with the gear tooth624 and gear slot 626.

The strut 620 includes a ring 634, a pair of upper radial plugs orprojections 636 disposed on opposite sides of the ring 634, and a pairof lower radial plugs or projections 638 disposed on opposite sides ofthe ring 634. The upper radial projections 636 and lower radialprojections 638 are aligned with each other.

To assemble a pair of disk segments 610 with the strut 620, the pair oflower radial projections 638 are inserted by sliding into the pair ofradial grooves 632 of a lower disk segment. An upper disk segment isoriented in an opposite direction from the lower disk segment, so thatthe pivoting side with the gear tooth 624, gear slot 626, and radialgrooves faces toward the strut 620. The pair of upper radial projections638 of the strut 620 are inserted by sliding into the pair of radialgrooves 632 of the upper disk segment. In the specific embodiment, theradial projections and radial grooves are circular cylindrical in shapeto facilitate pivoting between the disk segments. The gear tooth 624 ofthe lower disk segment is aligned with the gear slot 626 of the upperdisk segment to pivot relative thereto, while the gear tooth 624 of theupper disk segment is aligned with the gear slot 626 of the lower disksegment to pivot relative thereto. This is best seen in FIG. 51. Themovement between the gear tooth 624 and gear slot 626 is made by anothernonattached contact.

The proximal or first disk segment 611 is connected to the end of thetool shaft 602 by the mating extensions 622 of the disk segment 611 andmating extensions 603 of the shaft 602. The second disk segment 612 isoriented opposite from the first disk segment 611, and is coupled to thefirst segment 611 by a strut 620. The gear tooth 624 of the second disksegment 612 is engaged with the gear slot 626 of the first disk segment611, and the gear tooth 624 of the first disk segment 611 is engagedwith the gear slot 626 of the second disk segment 612. The third disksegment 613 is oriented opposite from the second disk segment 612, withtheir mating sides facing one another and the mating extensions 622mating with each other. The second disk segment 612 and the third disksegment 613 forms a whole disk. Similarly, the fourth disk segment 614and fifth disk segment 615 form a whole disk, and the sixth disk segment616 and the seventh disk segment 617 form another whole disk. The otherthree struts 620 are used to rotatably connect, respectively, third andfourth disk segments 613, 614; fifth and sixth disk segments 615, 616;and seventh and eighth disk segments 617, 618. The eighth or distal disksegment 618 is connected to the end effector 604 by the matingextensions 622 of the disk segment 618 and the mating extensions 605 ofthe end effector 604.

As more clearly seen in FIG. 53, the rotational coupling between thefirst disk segment 611 and second disk segment 612 provides pitchrotation 640 of typically about 45°, while the rotational couplingbetween the seventh disk segment 617 and eighth disk segment providesadditional pitch rotation 640 of typically about 45° for a total pitchof about 90°. The four disk segments in the middle are circumferentiallyoffset by 90° to provide yaw rotation. As more clearly seen in FIG. 54,the rotational coupling between the third disk segment 613 and fourthdisk segment 614 provides yaw rotation 642 of typically about 45°, whilethe rotational coupling between the fifth disk segment 615 and sixthdisk segment 161 provides additional yaw rotation 642 of typically about45° for a total yaw of about 90°. Of course, different orientations ofthe disk segments may be formed in other embodiments to achievedifferent combinations of pitch and yaw rotation, and additional disksegments may be included to allow the wrist to rotate in pitch and yawby greater than 90°.

Note that the rotatable engagement of the pair of projections 638 ofeach strut 620 with a respective bearing surface of grooves 632 on eachadjacent disk portion 610 assures a “dual pivot point” motion ofadjacent disks with respect to one another, such that the pivot pointsare in coplanar alignment with the cable apertures 630. By this means, a“cable balancing” property is achieved, to substantially similar effectas is described above with respect to the embodiment of FIG. 25. Thisassures that the cable length paid out on one side is equal to the cablelength pulled on the other side of the disk.

The disk segments of the wrist 600 are manipulated by six cables 650extending through the apertures 630 of the disk segments, as shown inFIGS. 55 and 56. Each cable passes through adjacent sets of apertures630 to make two passes through the length of the wrist 600 in a mannersimilar to that shown in FIG. 40, with the free ends extending throughthe tool shaft to the back end, where the cables are manipulated. Thesix cables include three long or distal cables and three short or medialcables that are alternately arranged around the disk segments. Aninternal lumen tube 654 may be provided through the center of the wrist600 and extend through the interior of the tool shaft 602, which is notshown in FIGS. 55 and 56. In the embodiment shown, the cables 650 arecrimped to hypotubes 656 provided inside the tool shaft 602.

FIGS. 57-63 show a gimbal mechanism 700 in the back end of the tool. Thegimbal mechanism 700 is more compact than the gimbal mechanismcomprising the gimbal plate and parallel linkage mechanism 340 of FIGS.35-40. The gimbal mechanism 700 includes another gimbal member or ring702 that is mounted to rotate around an axis 704. A gimbal plate oractuator plate 706 is mounted to the outer ring 700 to rotate around anorthogonal axis 708. A lock plate 710 is placed over the gimbal plate706. As seen in FIG. 59, the cables 650 from the wrist 600 are insertedthrough twelve cable holes 714, 716 of the gimbal plate 706, and pulledsubstantially straight back along arrow 716 toward the proximal end ofthe back end of the tool. The gimbal plate 706 includes six large radiusapertures 714 for receiving distal cables 650A and six small radiusapertures 716 for receiving medial cables 650B. The gimbal plate 706 hasa first actuator connection 718 and a second actuator connection 719 forconnecting to actuator links, as described below.

FIGS. 60 and 61 show the gimbal plate 706 and the lock plate 710 priorto assembly. The lock plate 710 is used to lock the cables 650A, 650B inplace by moving wedges against the cables 650. As best seen in FIG. 60,the lock plate has three outward wedges 720 with radially outward facingwedge surfaces and three inward wedges 722 with radially inward facingwedge surface, which are alternately arranged around the lock plate 710.The gimbal plate 706 has corresponding loose or movable wedges that matewith the fixed wedges 720, of the lock plate 710. As best seen in FIG.61, the gimbal plate 706 includes three movable inward wedges 730 withradially inward facing wedge surfaces and curved outward surfaces 731,and three movable outward wedges 732 with radially outward facing wedgesurfaces and curved inward surface 733. These movable wedges 730, 732are alternately arranged and inserted into slots providedcircumferentially around the gimbal plate 706.

The lock plate 710 is assembled with the gimbal plate 706 after thecables 650 are inserted through the cable holes 714, 716 of the gimbalplate 706. As the lock plate 710 is moved toward the gimbal plate 706,the three outward wedges 720 of the lock plate 720 mate with the threemovable inward wedges 730 in the slots of the gimbal plate 706 to pushthe movable inward wedges 730 radially outward against the six distalcables 650A extending through the six large radius apertures 714, whichare captured between the curved outward surfaces 731 of the wedges 730and the gimbal plate wall. The three inward wedges 722 of the lock plate720 mate with the three movable outward wedges 732 in the slots of thegimbal plate 706 to push the movable outward wedges 732 radially inwardagainst the six medial cables 650B extending through the six smallradius apertures 716, which are captured between the curved inwardsurfaces 733 of the wedges 732 and the gimbal plate wall. As seen inFIGS. 62 and 63, the lock plate 710 is attached to the gimbal plate 706using fasteners 738 such as threaded bolts or the like, which may beinserted from the gimbal plate into the lock plate 710, or vice versa.In this embodiment of crimping all cables 650 by attaching the lockplate 710 to the gimbal plate 706, the cable tension is not affected bythe termination method.

The gimbaled cable actuator 800 incorporating the gimbal mechanism 700as illustrated in the back end 801 FIGS. 64-67 is similar to thegimbaled cable actuator 300 of FIGS. 32-40, but are rearranged andreconfigured to be more compact and efficient. The gimbaled cableactuator 800 is mounted on a lower housing member of the back end andthe upper housing member is removed to show the internal details.

The gimbal plate 706 of the gimbal mechanism 700 is moved by a firstactuator link rotatably coupled to the first actuator connection 718 ofthe gimbal plate 706, and a second actuator link 806 rotatably coupledto the second actuator connection 719 of the gimbal plate 706, toproduce pitch and yaw rotations. The rotatable coupling at the firstactuator connection 718 and the second actuator connection 719 may beball-in-socket connections. The actuator links 804, 806 are driven tomove generally longitudinally by first and second follower gearquadrants 814, 816, respectively, which are rotatably coupled with theactuator links 804, 806 via pivot joints. The gear quadrants 814, 816are rotated by first and second drive gears 824, 826, respectively,which are in turn actuated by drive spools 834, 836. The gear quadrants814, 816 rotate around a common pivot axis 838. The arrangement is morecompact than that of FIGS. 32-40. The first and second actuator links804, 806 move in opposite directions to produce a yaw rotation of thegimbal plate 706, and move together in the same direction to produce apitch rotation of the gimbal plate 706. Mixed pitch and yaw rotationsresult from adjusting the mixed movement of the actuator links 804, 806.Helical drive gear 840 and follower gear 842 are used to produce rowrotation for improved efficiency and cost-effectiveness.

The back end 801 structure of FIGS. 64-67 provides an alternate way ofsecuring and tensioning the cables, including the support cables 462,464 for holding the grip support to the wrist (see FIGS. 38 and 38A),and grip actuation cables 446, 448 for actuating the opening and closingof the grip end effector (see FIG. 39). The support cables 462, 464 areclamped to an arm 860 which pivots around the pivot axis 838 and isbiased by a cable tensioning spring 862. The spring 862 biases the arm860 to apply tension to the support cables 462, 464 to hold the gripsupport tightly to the wrist (see FIGS. 38, 38A). The grip actuationcables 446, 448 extend around pulleys 870 (FIG. 66) connected to thespring-biased arm 860, and terminate at a pair of hub clamps 866, 868provided along the motor input shaft 870, as best seen in FIGS. 65 and67. The actuation cables 446, 448 are tensioned by applying a torque tothe hub clamps 866, 868.

FIG. 68A, 68B, and 68C illustrate schematically a PPMD wrist embodimentand corresponding actuator plate having aspects of the invention,wherein the wrist includes more than five segments or disks, and hasmore than one medial disk with cable termination. The PPMD wrist shownin this example has 7 disks (numbered 1-7 from proximal shaft end diskto distal end effector support disk), separated by 6 pivotal couplingsin a P,YY,PP,Y configuration. Three exemplary cable paths are shown, forcable sets c1, c2 and c3, which terminate at medial disks 3, 5 and 7respectively. FIG. 68A shows the wrist in a straight conformation, andFIG. 68B shows the wrist in a yaw-deflected or bent conformation. Thewrist may similarly be deflected in pitch (into or out of page), or acombination of these. Except for the number of segments and cable sets,the wrist shown is generally similar to the embodiment shown in FIGS.17-24.

The wrist shown is of the type having at least a pair of generallyparallel adjacent axes (e.g., . . . YPPY . . . or . . . PYYP . . . ),but may alternatively be configured with a PY,PY,PY alternatingperpendicular axes arrangement. Still further alternative embodimentsmay have combination configurations of inter-disk couplings, such asPYYP,YP and the like. The wrist illustrated has a constant segmentlength and sequentially repeated pivot axes orientations. In moregeneral alternative exemplary embodiments, the “Y” and “P” axes need notbe substantially perpendicular to each other and need not besubstantially perpendicular to the centerline, and the sequentialsegments need not be of a constant length.

FIG. 68C shows schematically the cable actuator plate layout, includingcable set connections at r1, r2 and r3, corresponding to cable sets c1,c2 and c3 respectively. Four connections are shown per cable set, butthe number may be 3, and may be greater than 4. In more general form,alternative PPMD wrist embodiment and corresponding actuator plateshaving aspects of the invention may be configured as follows: Where Nrepresents the number of disk segments (including end disks), the numberof cable termination medial disks M may be: M=(N−3)/2. The number ofcable sets and corresponding actuator plate “lever arm” radii, includingthe distal cable set connections, is M+1.

In general, the “constant velocity” segment arrangement describedpreviously is analogous to an even-numbered sequence ofuniversal-joint-like coupling pairs disposed back-to-front andfront-to-back in alternation. For example, a YP,PY or YP,PY,YP,PYsegment coupling sequence provides the “constant velocity” property.Thus may be achieved for arrangements wherein N−1 is a multiple of four,such as N=5, 9 and the like.

It may be seen that, for a given angular defection per coupling, theoverall deflection of the wrist increases with increasing segment number(the example of FIG. 68 B illustrates about 135 degrees of yaw).

The above-described arrangements of apparatus and methods are merelyillustrative of applications of the principles of this invention andmany other embodiments and modifications may be made without departingfrom the spirit and scope of the invention as defined in the claims. Thescope of the invention should, therefore, be determined not withreference to the above description, but instead should be determinedwith reference to the appended claims along with their full scope ofequivalents.

1. An apparatus comprising: a first actuator link; a first gear sectionrotatably coupled to the first actuator link to longitudinally move thefirst actuator link; a second actuator link; a second gear sectionrotatably coupled to the second actuator link to longitudinally move thesecond actuator link; an actuator plate comprising a mounting member,wherein the first and second actuator links are rotatably coupled to themounting member to move the actuator plate in pitch and yaw rotationswhen the first and second actuator links are longitudinally moved. 2.The apparatus of claim 1, further comprising: a parallel linkagecomprising a pair of parallel links coupled to the actuator plate; apair of parallel rings rotatably coupled to the pair of parallel links;a parallel linkage housing rotatably coupled to the pair of parallellinks via pivots to rotate the actuator plate.
 3. The apparatus of claim1, wherein the first and second actuator links are coupled to themounting member via ball-in-socket joints.
 4. The apparatus of claim 1,wherein the first and second gear sections comprise gear quadrants. 5.The apparatus of claim 1, further comprising: first and second drivegears coupled to the first and second gear sections to drive the firstand second gear sections; and first and second drive spools coupled toactuate the first and second drive gears, respectively.
 6. The apparatusof claim 1, the actuator plate further comprising a first plurality ofapertures having a first radius, and a second plurality of apertureshaving a second radius larger than the first radius.
 7. The apparatus ofclaim 6, further comprising: a shaft having a proximal end and a distalend, the proximal end coupled to the actuator plate; a flexible wristcoupled to distal end of the shaft, the flexible wrist comprising atleast one medial disk and at least one distal disk; a first plurality ofcables extending from the actuator plate through the first plurality ofapertures to the at least one medial disk of the flexible wrist; and asecond plurality of cables extending from the actuator plate through thesecond plurality of apertures to the at least one distal disk of theflexible wrist.
 8. The apparatus of claim 1, further comprising: A lowerhousing member, wherein the actuator plate is mounted on the lowerhousing member; An upper housing member mounted on the lower housingmember.
 9. The apparatus of claim 7, wherein a most distal disk of theat least one distal disk of the flexible wrist is coupled to an endeffector.
 10. An apparatus comprising: a mount; a gimbal ring coupled tothe mount to rotate about a first axis; an actuator plate mounted to thegimble ring to rotate about a second axis orthogonal to the first axis,the actuator plate comprising a first actuator connection and a secondactuator connection; and first and second actuator links rotatablycoupled to the first and second actuator connections, respectively, toproduce pitch and yaw rotations of the actuator plate.
 11. The apparatusof claim 10, the actuator plate further comprising a first plurality ofapertures having a first radius and a second plurality of apertureshaving a second radius larger than the first radius, the apparatusfurther comprising: a shaft having a proximal end and a distal end, theproximal end coupled to the actuator plate; a flexible wrist coupled tothe distal end of the shaft, the flexible wrist comprising at least onemedial disk and at least one distal disk; a first plurality of cablesextending from the actuator plate through the first plurality ofapertures to the at least one medial disk of the flexible wrist; and asecond plurality of cables extending from the actuator plate through thesecond plurality of apertures to the at least one distal disk of theflexible wrist.
 12. The apparatus of claim 11, further comprising a lockplate coupled to the actuator plate, the lock plate comprising at leastone wedge configured to mate with at least one corresponding wedge inthe actuator plate to lock the first and second plurality of cables inplace.
 13. The apparatus of claim 10, further comprising a first gearsection rotatably coupled to the first actuator link to longitudinallymove the first actuator link and a second gear section rotatably coupledto the second actuator link to longitudinally move the second actuatorlink.
 14. A tendon actuating assembly for a surgical instrument, whereinthe instrument includes a shaft-like member having a distal working endfor insertion into a patient's body through an aperture, the working endincluding at least one distal moveable member arranged to be actuated byat least one of a plurality of movable tendon element, the actuatingassembly comprising: a tendon actuator member, the actuator memberconfigured to be movable to at least pivot in one degree of freedom, theactuator member including a plurality of tendon engagement portions,each engagement portion being drivingly couplable to at least one of theplurality of tendons; a drive mechanism drivingly coupled to theactuator member so as to controllably pivot the actuator member in theat least one degree of freedom, so as to move at least one of thetendons relative to the shaft-like member so as to actuate the distalmoveable member.
 15. The actuating assembly of claim 14, wherein thetendon actuator member is pivotable about at least one pivot axis, andeach engagement portion is spaced apart from at least one of the pivotaxes, the drive mechanism being configured to controllably pivot theactuator member about the at least one pivot axes, so as to move atleast one tendon relative to the shaft-like member so as to actuate thedistal moveable member.
 16. The actuating assembly of claim 14, whereinthe tendon actuator member is pivotable about at least a first pivotaxis and a second pivot axis; at least one of the plurality of tendonengagement portions is space apart from at least the first pivot axisand at least one of the plurality of tendon engagement portions is spaceapart from at least the second pivot axis; the drive mechanismconfigured to controllably pivot the actuator member selectably about ateach of the pivot axes, so that movement of the actuator member abouteither of the pivot axes moves at least one tendon relative to theshaft-like member so as to actuate the at least one distal moveablemember.
 17. The actuating assembly of claim 16, including a plurality oftendons coupled to a plurality of engagement portions spaced apart fromat least the first pivot axis, and a plurality of tendons coupled to aplurality of engagement portions spaced apart from at least the secondpivot axis, so that selectable pivoting of the actuator member abouteither of the pivot axes moves a plurality of tendons relative to theshaft-like member so as to actuate the at least one distal moveablemember.
 18. The actuating assembly of claim 17, wherein different onesof at least the plurality of engagement portions spaced apart from atleast one of the first and second pivot axes are spaced at differentdistances from the at least one axis, so that selectable pivoting of theactuator member about the at least one axis moves different ones of therespective coupled tendons by different amounts relative to theshaft-like member.
 19. The actuating assembly of claim 18, wherein theactuator member has a central axis; each of the first and second pivotaxes intersect central axis; the plurality of engagement portionsincludes a first set of more than one engagement portions spaced apartfrom the central axis at about a first radial distance.
 20. Theactuating assembly of claim 19, wherein the plurality of engagementportions includes at least a second set of more than one engagementportions spaced apart from the central axis at about a second radialdistance, the first radial distance being substantially different fromthe second radial distance.
 21. The actuating assembly of claim 19,wherein the plurality of engagement portions includes a plurality ofdifferent sets of at least three engagement portions, each set spacedapart from the central axis at about a radial distance, the radialdistance of each of the plurality of set being substantially differentfrom the radial distance of each of the other sets.
 22. The actuatingassembly of either of claim 20 or 21, wherein the at least one distalmovable member is a movable segment of a distal flexible member.
 23. Theactuating assembly of either of claim 20 or 21, wherein the drivemechanism is controllable by a robotic surgical system.
 24. A segmentpivoted coupling mechanism for pivotally coupling two adjacent segmentvertebrae of a multi-segment flexible member of a medical instrument,the two adjacent segments having bending direction with respect to oneanother, the flexible member having at least one neutral bending axis,the instrument including at least two movable actuation tendon passingthrough at least two apertures in each adjacent vertebrae, wherein theat least two apertures in each of the vertebra are spaced apart onopposite sides of the neutral axis with respect to the pivot direction,and wherein openings of the apertures are disposed one adjacent surfacesof the two vertebrae so as to generally define an aperture plane, thecoupling mechanism comprising: at least one inter-vertebral engagementelement coupled to each of the vertebrae, the element pivotally engagingthe vertebrae so as to define at least two spaced-apart parallelcooperating pivot axes, each one of the pivot axes being alignedgenerally within the aperture plane of a respective one of the adjacentvertebra, so as to provide that each vertebra is pivotally movable aboutits respective pivot axis, so as to balance the motion of the tendons onopposite sides of the neutral axis when the flexible member is deflectedin the bending direction.
 25. The segment pivoted coupling mechanism ofclaim 24, wherein the pivot axes are virtual axes; the at least oneengagement element is a cooperating opposed pair of elements each havinga contour in movable contact with the other; and the engagement contoursare shaped to produce the virtual axes as the vertebra are move relativeto one another in the bending direction.
 26. The segment pivotedcoupling mechanism of claim 24, wherein the at least one engagementelement is an engagement strut having at least one opposed space-apartpair of bearing portions, each bearing portion engaging a respective oneof the vertebrae at an engagement point generally within the apertureplane of the vertebra, so as to define a pivot axis in each apertureplane.